The present invention relates to electronics assemblies, and is primarily concerned with racked assemblies. Many such assemblies will be located in racks for housing in for example nineteen inch cabinets, or other size cabinets such as twenty three inch or metric cabinets. The assemblies may for instance be employed as servers for a number of systems, for example in local area networks (LANs), wide area networks (WANs), telecommunications systems or other operations such as database management or as internet servers.
Such an assembly will typically comprise a supporting frame or chassis that houses a motherboard or backplane and a number of daughterboards or module cards that extend in planes generally perpendicular to the plane of the motherboard and which are connected to the motherboard by connectors, e.g. high density connectors, so that the daughterboards can simply be located on guides and pushed toward the motherboard in order to connect them to it. Often only a single assembly will be located in a cabinet, but in many cases more than one, for example two, such assemblies will be housed in the cabinet, one above the other.
In addition, the motherboard may need to be removed for general maintenance purposes, upgrading or the like and so the frame of the assembly will normally provide for removal of the motherboard therefrom and re-insertion therein.
However, the motherboard can be relatively heavy, weighing in the region of 10 kg, and some form of support may be needed for the module as it is being removed from, and re-installed in, the frame.
According to one aspect, the invention provides an electronics assembly which comprises
(i) a frame; and
(ii) a generally planar, horizontal motherboard module that is removable by lowering the module from the bottom of the frame and which can be replaced by raising the module up to engage the bottom of the frame and securing it in position on the frame by means of one or more securing elements,
wherein the frame and the motherboard module have co-operating temporary supporting elements that can be engaged to support one edge of the motherboard module until the or at least some of the securing elements have been engaged to secure the motherboard module to the frame or after the securing elements have been released.
According to another aspect, the invention provides a frame for an electronics assembly to which a generally planar motherboard module can be attached by raising the motherboard module up from below the frame, the frame including at least one temporary supporting element, arranged on side therefore, that can co-operate with the motherboard module to support the module along one edge thereof.
According to a further aspect, the invention provides a motherboard module for attachment to the frame of an electronics assembly to provide a motherboard therefore, the module having one or more temporary supporting elements on one edge thereof that can engage the frame to support that edge of the module on the frame.
The assembly according to the invention may be one in which the motherboard is arranged in a generally horizontal plane and is located beneath the daughterboards, the daughterboards being slid along vertical card guides into and out of engagement with connectors located on the motherboard. In this case, the motherboard needs to be located accurately with respect to the card guides for the daughterboards and therefore with the frame of the assembly in which the daughterboards are housed. One simple method of accurately locating the motherboard with respect to the frame is to house the motherboards in a module having a generally planar support for the motherboard, and to offer up the motherboard module to the frame before securing the module to the frame by means of securing elements such as screws. The motherboard module and the frame may be, provided if desired, with guidance and location elements such as pins that are engaged in corresponding holes in order to ensure exact positioning of the motherboard with respect to the frame in a horizontal plane. Such an arrangement is relatively simple and provides mode accurate location of the motherboard in the frame than systems in which the motherboard can be slid into the frame in its own plane since such systems necessarily require lower tolerances for fitting the motherboard to the frame.
Once the motherboard module can be supported at one edge, it becomes relatively easy for a service engineer to support the motherboard module with one hand while securing it to the frame with the other.
The temporary supporting elements on the frame and on the motherboard module may together form a hinge that will support one edge portion of the motherboard module and will allow the opposite edge therefore to be raised and lowered by the service engineer as required before securing the motherboard module or after it has been unsecured from the frame. It is possible, if desired, to arrange the temporary supporting elements, or arrange other parts of the assembly, to allow the opposite edge portion of the motherboard module to be lowered only by a predetermined amount, or alternatively it can be allowed to be lowered until it rests on the floor or on any lower equipment in the cabinet.
In one form of assembly according to the invention the temporary supporting element on the frame or on the motherboard module can simply be in the form of a flange that can engage a corresponding flange, hooks or other structure on the other of the frame on the motherboard module.
Alternatively, the temporary supporting element on one of the frame and the motherboard module can be in the form of one or more pins, hooks or other elements that can engage one or more holes in the other of the frame and the module so that the point at which the pins engage the holes acts as a hinge point for pivoting of the motherboard module. Usually the pins will be located on the motherboard module and will engage holes in the rear of the frame.
It is possible for the holes that receive the pins to be circular, but this does not allow movement of the motherboard module in the vertical direction if required when engaging the securing elements. Accordingly, the holes in the frame, or in the motherboard module, if the pins are located on the frame, are elongate in the vertical direction. This allows some relative vertical movement between the frame and the motherboard module, and allows, for example, the motherboard module to be lifted off the temporary supporting element on the frame when the, or at least some of the, securing elements are engaged.
The relative vertical movement of the motherboard module and the frame may be useful to compress an electromagnetic interference (EMI) gasket when engaging the securing element(s). For example if, as will usually be the case, screws are employed as the securing elements, some vertical movement of the motherboard module will be likely when tightening the screws.
Guidance elements may be included on the frame and/or on the motherboard module for locating the motherboard module with respect to the frame in a horizontal plane rather than simply relying on the securing elements to perform the positioning.
Support may be provided to one or more edges/corners of the motherboard module. For example, attachment elements could be provided on the edge of the the motherboard module and/or of the frame located opposite that edge on which the temporary supporting elements are located so that the motherboard module can be supported below the frame in a horizontal plane without the need for the service engineer to use any hands at all to support the motherboard module while engaging the securing elements.
According to yet another aspect, the invention provides a method of attaching a motherboard module to the frame of an electronics assembly, which comprises
(i) raising up the motherboard module from below the frame and attaching one edge of the motherboard module to a lower edge of the frame by means of co-operating temporary supporting elements located on the motherboard module and on the frame;
(ii) lifting the opposite edge of the motherboard module toward the frame to locate the motherboard module in a generally horizontal plane at the bottom of the frame; and
(iii) securing the motherboard module to the frame by means of one or more securing elements while manually supporting the said opposite edge of the motherboard module.